1. Field of the Invention
The present invention generally relates to a power management method, in particular, to a power management method adaptable to an electronic device having multiple operating systems.
2. Description of Related Art
To keep up with the bustling pace of modern human life, various portable and space-saving electronic devices have been put forward one after another. For example, smart phones are not only equipped all functions of a conventional communication device, but also allow users to achieve purposes such as document writing, E-mail receiving/sending, network accessing, or the use of real-time communication software through a built-in Windows operating system (Windows OS). That is to say, such hand-held communication devices may not only be used to make phone calls, but also serves as a miniature PC with versatile functions. Further, with the progress of wireless network technology, those functions can be used free from time and space limitations. Therefore, such devices have become an indispensable tool in a modern life in pursuit of efficiency.
The architecture of such hand-held communication devices has an embedded system, and works through a Windows mobile OS such as Windows CE. However, the function of the Windows mobile OS may be limited by the performance of the processor used in the hand-held communication device, and cannot achieve the multiplexed and diversified functions of an ordinary computer operating system. For example, a Windows OS such as Windows XP or Windows VISTA used in a PC is capable of processing complicated tasks like text edition and frame processing, thus having a higher performance as compared with the Windows mobile OS. In order to improve the performance of the portable electronic devices, a brand new architecture integrating the portability of the Windows mobile OS and functionality of the Windows OS of a PC is developed.
In an actual application of foregoing system having dual operating systems, system resources are shared by the two operating systems, wherein one of the operating systems stands by while the other operating system works. When a user is about to stop the currently used operating system and switch to the other operating system, the user needs to press a switch button on the electronic device to switch to the desired operating system, and meanwhile, the interface displayed on the screen of the electronic device is also switched.
However, in foregoing system having dual operating systems, a processor is disposed in regard to each of the operating systems to execute the tasks assigned by the operating system. In an actual application, only the processor of one of the operating systems is used for executing tasks, and only the user interface of this operating system is displayed on the screen of the electronic device, and accordingly, the power supplied to the other operating system is wasted. Thereby, a suitable mechanism for managing the power supplied to two operating systems in an electronic device is required in order to reduce the power consumption of the electronic device and prolong the lifespan of a battery in the electronic device.